21: Entrapment Neuropathies - Bennett

Question 1

outer connective tissue layer that supports the nerve from compression injury

Answer 1

epineurium

Question 2

group of nerve fibers supported by perineurium

Answer 2

fasicle

Question 3

named connective tissue utilized to support and protect the fascicles

Answer 3

perineurium

Question 4

compression injury, resulting in myelin sheath degeneration. there is conduction deficit without axonal destruction

Answer 4

neurapraxia

Question 5

axonal and myelin sheath disruption without disruption of endoneurial tube

Answer 5

axonotmesis

Question 6

gross nerve disruption

Answer 6

neurotmesis

Question 7

sunderland classification of nerve injury

Answer 7

1st degree: conduction deficit without axonal damage

2nd: axon severed without breaching endoneurium
3rd: disorganization of internal fascicles
4th: axonal rupture with perineurial disruption
5th: complete loss of continuity

Question 8

seddon grade and sunderland grade classification

Answer 8

neurapraxia = 1

axonotmesis - 2-4

neurotmesis = 5

*** draw out corresponding slide in notes

Question 9

mechanism of neuropathy with entrapment

Answer 9

compression

Question 10

classification of neuropathies by mechanism:
GB
metabolic etiologies
diabetes
n. transection
polyarteritis nodosa
leprosy, CMV

Answer 10

demyelination
axonal
segmental
wallerian
infarction
inflammation

Question 11

exogenous v. endogenous

Answer 11

exogenous: direct trauma, repeated microtrauma, neuroma-in-continuity, space occupying lesions
endogenous: compartment syndrome, intraneural hematoma

Question 12

cast pressure

Answer 12

exogenous etiologies

common peroneal n. as it courses around fibular head, inappropriate cast application

Question 13

improper tourniquet use

Answer 13

exogenous

inadequate padding or positioning or prolongation of tourniquet time

Question 14

biomechanical

Answer 14

exogenous

pronation with excessive pressure on teh n. compartment with respect to tarsal tunnel

Question 15

compartment syndrome

Answer 15

endogenous etiology

edema of fascial compartments of the leg or foot leading to n. compression that will cause n. infarction if the fascial compartments are not decompressed

Question 16

intraneural hematoma

Answer 16

endogenous etiologoy

direct n. contusion or from injection that causes intraneural bleeding and compression

Question 17

meralgia paraesthetica

Answer 17

lateral cutaneous n. of the thigh

nerve compressed under the inguinal ligament, causes burning sensation over anterolateral thigh

Question 18

compression of the n. at fibular neck

Answer 18

common peroneal n.

n. courses around fibular neck piercing the two heads of peroneus longus - injury leads to weakness of tibialis anterior and resultant foot drop. altered snesation over lateral leg and dorsum foot may also be experienced

Question 19

tight fitting shoes –>

Answer 19

superficial peroneal nerve

Question 20

anterior tarsal tunnel =

Answer 20

deep peroneal nerve entrapped in the anterior ankle and dorsum of foot

most commonly as it passes under the muscle and tendon of the extensor hallucis brevis

Question 21

where is the sural n. commonly entrapped?

Answer 21

in scar tissue following achilles or lateral ankle surgery

can also be entrapped as its branches pierce the lateral fascia of the leg

Question 22

tarsal tunnel =

Answer 22

deep to laciniate ligament

Question 23

abductor canal =

Answer 23

medial plantar n. entrapment between abductor hallucis muscle and spring ligament

Question 24

plantar vault =

Answer 24

lateral plantar nerve entrapement between abductor hallucis m. and quadratus plantae

Question 25

where is an intermetatarsal neuroma commonly found?

Answer 25

third intermetatarsal space

occurs here because medial and lateral plantar n. contribute branches to this spae

Question 26

tinel’s sign

Answer 26

tapping directly over the n. that causes numbness and tingling at the site

Question 27

villioux sign

Answer 27

tapping directly over the n. that cuases radiating sensations either, or both proximal and distal

Question 28

epicritic sensations

Answer 28

vibratory
sharp-dull
crude touch
light touch
 DTR
plantar reponse
kinesthetic snese

Question 29

if vena comitans is suspected etiology ….

Answer 29

tourniquet test

Question 30

saphenous n.

Answer 30

spinal level L3-4

Question 31

common peroneal n.

Answer 31

spinal level L4/5 S1

Question 32

superficial peroneal n.

Answer 32

spinal level L4/5, S1

Question 33

deep peroneal n.

Answer 33

spinal level L4/5 S1

*paresthesias in first web space

Question 34

sural n.

Answer 34

L5 S1/2

Question 35

tibial n.

Answer 35

L4/5 S1-3

Question 36

most common entrapment neuropathy experience d in foot

Answer 36

morton’s neuroma

numbess tingling to third and fourth toes with pinching pain under the ball of the foot

Question 37

positive mulder’s click

Answer 37

thrid interspace

= morton’s neuroma